{"id":885,"date":"2020-02-11T16:42:55","date_gmt":"2020-02-11T20:42:55","guid":{"rendered":"https:\/\/www2.whoi.edu\/site\/aomip\/?page_id=885"},"modified":"2021-06-18T09:34:08","modified_gmt":"2021-06-18T13:34:08","slug":"radiative-heat-fluxes","status":"publish","type":"page","link":"https:\/\/www2.whoi.edu\/site\/aomip\/data\/atmospheric-forcing-data\/radiative-heat-fluxes\/","title":{"rendered":"Radiative Heat Fluxes"},"content":{"rendered":"\n\n\t<h1>Radiative Heat Fluxes<\/h1>\n<p>Radiative fluxes are defined with the sign convention that an upward directed flux is a positive quantity.<\/p>\n<h2>Shortwave<\/h2>\n<p>The prescription of shortwave radiation follows that of\u00a0<a href=\"https:\/\/www2.whoi.edu\/site\/aomip\/references\/#Parkinson_1979\">Parkinson and Washington<\/a>\u00a0(1979) and\u00a0<a href=\"https:\/\/www2.whoi.edu\/site\/aomip\/references\/#Zillman_1972\">Zillman<\/a>\u00a0(1972).<\/p>\n<p>For the ocean surface, the net\u00a0<em>downward<\/em>\u00a0shortwave radiation (W\/m<sup>2<\/sup>) is modeled as<\/p>\n\n<p>For the ice (snow) surface, the net\u00a0<em>downward<\/em>\u00a0shortwave radiation (W\/m<sup>2<\/sup>) is modeled in an analogous manner as<\/p>\n\n<p>The amount of shortwave radiation, prior to its modification by cloud cover and surface albedo effects as formulated above, is the Zillman relation<\/p>\n\n<p>where <img loading=\"lazy\" src=\"https:\/\/www2.whoi.edu\/site\/aomip\/wp-content\/uploads\/sites\/100\/2020\/02\/zenith_angle_84931.gif\" alt=\"z\" width=\"20\" height=\"21\" \/>\u00a0is the solar zenith angle, whose cosine is calculated by the geometric formula<\/p>\n\n<p><img loading=\"lazy\" src=\"https:\/\/www2.whoi.edu\/site\/aomip\/wp-content\/uploads\/sites\/100\/2020\/02\/solar_constant_84929.gif\" alt=\"Solar Constant\" width=\"25\" height=\"30\" \/>is the solar constant, and<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/www2.whoi.edu\/site\/aomip\/wp-content\/uploads\/sites\/100\/2020\/02\/vapor_press_air_84930.gif\" alt=\"the vapor pressure of water in air\" width=\"20\" height=\"30\" \/> \u00a0is the vapor pressure of water in air.<\/p>\n<p>In the above formula for shortwave radiation,<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/www2.whoi.edu\/site\/aomip\/wp-content\/uploads\/sites\/100\/2020\/02\/latitude_84923.gif\" alt=\"geographic latitude\" width=\"16\" height=\"26\" \/> is the geographic latitude, and<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/www2.whoi.edu\/site\/aomip\/wp-content\/uploads\/sites\/100\/2020\/02\/declination_84917.gif\" alt=\"declination\" width=\"18\" height=\"23\" \/>\u00a0is the declination as determined by<\/p>\n\n\n<p>is the day-of-year, expressed in 365-day format.<\/p>\n<p>Care has to be taken for solar zenith angles outside the range<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/www2.whoi.edu\/site\/aomip\/wp-content\/uploads\/sites\/100\/2020\/02\/zenith_angle_bound_84932.gif\" alt=\"Zenith Angle Bound\" width=\"105\" height=\"51\" \/>that the solar radiation is set to zero<\/p>\n<p>(i.e., the sun is below the local horizon in such cases).<\/p>\n<p>Finally, <img loading=\"lazy\" src=\"https:\/\/www2.whoi.edu\/site\/aomip\/wp-content\/uploads\/sites\/100\/2020\/02\/hour_angle_84919.gif\" alt=\"hour angle\" width=\"23\" height=\"21\" \/>\u00a0is the hour angle given by<\/p>\n\n\n<p>is the hour-of-day, expressed in 24-hour format.<\/p>\n<p>The above parameterization of shortwave radiation explicitly accounts for the diurnal cycle of radiation. Models with time steps in excess of 1 hour or so are to be careful that their representation of shortwave radiation is meaningful. A suggestion for such models is to simply eliminate any attempt at resolving the diurnal cycle by instead taking the daily averaged shortwave radiation.<\/p>\n<p>All angles in the above formulae are expressed in radians.<\/p>\n<h2>Longwave<\/h2>\n<p>For the ocean surface, the net upward longwave radiation (W\/m<sup>2<\/sup>) is modeled (<a href=\"https:\/\/www2.whoi.edu\/site\/aomip\/references\/#Rosati_1988\">Rosati and Miyakoda<\/a>, 1988)<\/p>\n\n<p>For the ice (snow) surface, the net upward longwave radiation (W\/m<sup>2<\/sup>) is modeled in an analogous manner as<\/p>\n\n<p>NOTE: All temperatures involved in longwave calculations are in Kelvin.<\/p>\n\n","protected":false},"excerpt":{"rendered":"<p>Radiative Heat Fluxes Radiative fluxes are defined with the sign convention that an upward directed flux is a positive quantity. Shortwave The prescription of shortwave radiation follows that of\u00a0Parkinson and Washington\u00a0(1979) and\u00a0Zillman\u00a0(1972). For the ocean surface, the net\u00a0downward\u00a0shortwave radiation (W\/m2) is modeled as For the ice (snow) surface, the net\u00a0downward\u00a0shortwave radiation (W\/m2) is modeled in&hellip;<\/p>\n","protected":false},"author":83,"featured_media":0,"parent":805,"menu_order":10,"comment_status":"closed","ping_status":"closed","template":"tpl-sidebar.php","meta":{"advanced-sidebar-menu\/link-title":"","advanced-sidebar-menu\/exclude-page":false},"_links":{"self":[{"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages\/885"}],"collection":[{"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/users\/83"}],"replies":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/comments?post=885"}],"version-history":[{"count":3,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages\/885\/revisions"}],"predecessor-version":[{"id":1701,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages\/885\/revisions\/1701"}],"up":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages\/805"}],"wp:attachment":[{"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/media?parent=885"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}